Amplified Q-Switched Solid-State Laser And Its Interaction With Material

Solid-state laser became these days of great importance where it involved in many applications because several major innovations expanded their capability. Among these applications is laser-induced plasma spectroscopy LIPS, sometimes namely optical emission spectroscopy of laser-induced plasmas, which also have been constantly growing thanks to its intrinsic conceptual simplicity and versatility. The great progress in the solid-state laser technology gives the application laser-induced plasma spectroscopy its importance. Solid-state laser system can operated in different modes. Each mode has its own characteristics, which determine the available different applications. Among the wide different modes of operation for the solid-state laser system are long-pulse, normal-mode,Q-switched and amplified mode of operation. Amplified mode of operation means laser amplifier. For each mode of operation there are different mechanisms inside the solid-state laser system controlling the system performance from the electrical energy input to the flashlamp to the laser pulse output from the oscillator. Different mechanisms inside any solid-state laser system could be studied from different point of view. Major innovations are presented with emphasis focused on the laser efficiency. A product of the different efficiency factors approach is developed and applied to describe laser performance. Laser pulse from the different modes of operation for the solid-state laser system, especially; long-pulse (msec), normal-mode (μsec) and Q-switched (nsec) modes of operation, has a great interest in the interaction with materials. Laser-induced plasma spectroscopy LIPS has become a very popular analytical method in the last decade in view of some of its unique features such as (applicability to any type of sample, practically no sample preparation, remote sensing capability, and speed of analysis. The technique has a remarkably wide applicability in many fields, and the number of applications is still growing.A design for the solid-state laser system from the point of view of the different Efficiency factors inside the laser system was done for long-pulse, normal-mode,Q-switched and amplified mode of operation. The design is concentrated on the laser system performance; it will deal with the laser system performance from the point of view of engineering. The design criteria will presented arithmetically accompanied by experimental work to verify the exactness of the calculated data arithmetically. The pump cavity used in the experimental work will be designed, and the design considerations will be presented. The designed pump cavity has the geometry of ellipse. Double-elliptical pump cavity will be designed for the long-pulse mode of operation and single-elliptical pump cavity will be designed for the normal-mode,Q-switched and amplified modes of operation. The stability criterion for the active optical resonator will be checked through ABCD matrix of the various optical components inside the resonator for one round-trip. In addition, the ABCD matrix will be used to get the pump cavity separation margins from the rear and output mirror. The optical resonator loss inside the optical resonator will be calculated experimentally by operating the solid-state laser system with different output mirror reflectivity, to withstand on the practical value for the resonator loss. An analysis for the different parameters controlling the solids-state laser system will be done for the long-pulse solid state mode of operation, such as; gain coefficient and single-pass gain, inverted density, fluorescence power, intracavity power density with the output power and output mirror reflectivity and output beam parameter. From the experimental work, the maximum attainable output energy from the long-pulse solid-state laser system is10Jwith pulse width20msec for overall system efficiency0.335%and maximum input energy4215J, while the maximum attainable output energy from the normal-mode solid-state laser system is400mJ with pulse width125μsec for overall system efficiency1.21%and maximum input energy25.92J. A174mJ output energy with pulse width9nsec will be obtained from the Q-switched mode of operation for overall system efficiency1.045%with input energy25.92J. For the amplified mode of operation, the energy output from the amplifier is446mJ for laser pulse input energy to the amplifier202.62mJ with gain2.22and for electrical input energy to the flashlamp25.92J with overall system efficiency2.82%.The laser pulse produced from the three modes of operation; long-pulse (msec), normal-mode (μsec) and Q-switched (nsec) modes of operation, will be interacted with epoxide resin target, by focusing the output laser pulse through a focusing lens into target surface. There are two different laser pulses for the millisecond laser source according to two different focusing lenses, while for the microsecond and nanosecond laser pulses, there are two repetition rates used for the laser source;10Hz and5Hz. Each laser pulse regime (msec, μsec, nsec) has its own power densities, and all produce plasma emission from the interaction with the epoxide resin material. For the first time to the best of our knowledge, Nd:YAG laser pulse1064nm with power density of around8x104W/cm2that can produce plasma Spectroscopy LIPS emission from a solid target. The electron density inferred through the Saha-Boltzmann equation for eight line ratios of C Ⅰ and CⅡ lines, for the millisecond and nanosecond laser pulses but cannot determined for the microsecond laser pulse as there was no sufficient data. The electron temperature was determined using the Boltzmann plot method for the millisecond laser pulse with small spot pulse size and nanosecond laser pulse with the repletion rates10Hz and5Hz, and using line pair method for the millisecond laser pulse with large spot size. The maximum plasma temperature and electron density recorded from the plasma emission (from the62.87GW/cm2nanosecond laser pulse,10Hz) were20410°K and5.04x1020cm-3respectively. On the other hand, the plasma temperature and electron density for the plasma emitted from millisecond laser pulse with large spot size (irradiance around105W/cm2) were10924°K and7.39x1017cm-3respectively. Electron density and electron temperature were also studied as functions of laser power density for the different laser pulses. At the same time, the validity of the assumption of local thermodynamic equilibrium was discussed in light of the results obtained.